Physiological monitoring device

ABSTRACT

The present invention relates to a physiological monitoring device. Some embodiments of the invention allow for long-term monitoring of physiological signals. Further embodiments may also allow for the monitoring of secondary signals such as motion.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.16/006,719, filed Jun. 12, 2018, which is a continuation of Ser. No.14/162,656, filed, Jan. 23, 2014, which claims the benefit of U.S.Provisional Application No. 61/756,326, filed Jan. 24, 2013, entitledPHYSIOLOGICAL MONITORING DEVICE. The contents of the aforementionedapplications are hereby incorporated by reference in their entireties asif fully set forth herein. The benefit of priority to the foregoingprovisional application is claimed under the appropriate legal basis,including, without limitation, under 35 U.S.C. § 119(e).

BACKGROUND Field of the Invention

The invention relates generally to medical devices. More specifically,the invention relates to a physiological monitoring device and methodfor use.

Description of the Related Art

Abnormal heart rhythms, or arrhythmias, may cause various types ofsymptoms, such as loss of-consciousness, palpitations, dizziness, oreven death. An arrhythmia that causes such symptoms is often anindicator of significant underlying heart disease. It is important toidentify when such symptoms are due to an abnormal heart rhythm, sincetreatment with various procedures, such as pacemaker implantation orpercutaneous catheter ablation, can successfully ameliorate theseproblems and prevent significant symptoms and death.

Since the symptoms listed above can often be due to other, less seriouscauses, a key challenge is to determine when any of these symptoms aredue to an arrhythmia. Oftentimes, arrhythmias occur infrequently and/orepisodically, making rapid and reliable diagnosis difficult. Currently,cardiac rhythm monitoring is primarily accomplished through the use ofdevices, such as Holter monitors, that use short-duration (<1 day)electrodes affixed to the chest. Wires connect the electrodes to arecording device, usually worn on a belt. The electrodes need dailychanging and the wires are cumbersome. The devices also have limitedmemory and recording time. Wearing the device interferes with patientmovement and often precludes performing certain activities while beingmonitored, such as bathing. All of these limitations severely hinder thediagnostic usefulness of the device, the compliance of patients usingthe device and the likelihood of capturing all important information.Lack of compliance and the shortcomings of the devices often lead to theneed for additional devices, follow-on monitoring or other tests to makea correct diagnosis.

Current methods to correlate symptoms with the occurrence ofarrhythmias, including the use of cardiac rhythm monitoring devices,such as Holter monitors and cardiac event recorders, are often notsufficient to allow an accurate diagnosis to be made. In fact, Holtermonitors have been shown to not lead to a diagnosis up to 90% of thetime (“Assessment of the Diagnostic Value of 24-Hour AmbulatoryElectrocariographic Monitoring”, by DE Ward et al. Biotelemetry PatientMonitoring, vol. 7, published in 1980).

Additionally, the medical treatment process to actually obtain a cardiacrhythm monitoring device and initiate monitoring is typically verycomplicated. There are usually numerous steps involved in ordering,tracking, monitoring, retrieving, and analyzing the data from such amonitoring device. In most cases, cardiac monitoring devices used todayare ordered by a cardiologist or a cardiac electrophysiologist (EP),rather than the patient's primary care physician (PCP). This is ofsignificance since the PCP is often the first physician to see thepatient and determine that the patient's symptoms could be due to anarrhythmia. After the patient sees the PCP, the PCP will make anappointment for the patient to see a cardiologist or an EP. Thisappointment is usually several weeks from the initial visit with thePCP, which in itself leads to a delay in making a potential diagnosis aswell as increases the likelihood that an arrhythmia episode will occurand go undiagnosed. When the patient finally sees the cardiologist orEP, a cardiac rhythm monitoring device will usually be ordered. Themonitoring period can last 24-48 hours (Holter monitor) or up to a month(cardiac event monitor or mobile telemetry device). Once the monitoringhas been completed, the patient typically must return the device to theclinic, which itself can be an inconvenience. After the data has beenprocessed by the monitoring company or by a technician on-site at ahospital or office, a report will finally be sent to the cardiologist orEP for analysis. This complex process results in fewer patientsreceiving cardiac rhythm monitoring than would ideally receive it.

To address some of these issues with cardiac monitoring, the assignee ofthe present application developed various embodiments of a small,long-term, wearable, physiological monitoring device. One embodiment ofthe device is the Zio® Patch (www.irhythmtech.com). Various embodimentsare also described, for example, in U.S. Pat. Nos. 8,150,502, 8,160,6828,244,335, 8,560,046, and 8,538,503, the full disclosures of which arehereby incorporated by reference. Generally, the physiological monitorsdescribed in the above references fit comfortably on a patient's chestand are designed to be worn for at least one week and typically two tothree weeks. The monitors detect and record cardiac rhythm signal datacontinuously while the device is worn, and this cardiac rhythm data isthen available for processing and analysis.

These smaller, long-term physiological monitoring devices provided manyadvantages over prior art devices. At the same time, furtherimprovements are desired. One of the most meaningful areas forimprovement exists around increasing fidelity of the recorded ECGsignal. This is particularly important for single-channel embodimentswhere a second vector of ECG is not available to clarify whetheraberrances in signal are due to arrhythmia or signal artifact. Increasesin signal to noise ratio as well as reduction of motion artifact improveefficiency in both algorithmic and human analysis of the recorded ECGsignal.

Signal quality is important throughout the duration of wear, but it isparticularly critical where the patient marks the record, indicating anarea of symptomatic clinical significance. Marking the record is mosteasily enabled through a trigger located on the external surface of thedevice. However, since the trigger is part of a skin-contacting platformwith integrated electrodes, the patient can introduce significant motionartifacts when feeling for the trigger. A desirable device improvementwould be a symptom trigger that can be activated with minimal additionof motion artifact.

Secondly, patient compliance and device adhesion performance are twofactors that govern the duration of the ECG record and consequently thediagnostic yield. Compliance can be increased by improving the patient'swear experience, which is affected by wear comfort, device appearanceand the extent to which the device impedes the normal activities ofdaily living. Given that longer ECG records provide greater diagnosticyield and hence value, improvements to device adhesion and patientcompliance are desirable.

Finally, it is desirable for the device to be simple and cost effectiveto manufacture, enabling scalability at manufacturing as well as higherquality due to repeatability in process. Simplicity of manufacture canalso lead to ease of disassembly, which enables the efficient recoveryof the printed circuit board for quality-controlled reuse in anotherdevice. Efficient reuse of this expensive component is critical fordecreasing the cost of the diagnostic monitor. At least some of theobjectives will be met by the embodiments described below.

BRIEF SUMMARY

Embodiments described herein are directed to a physiological monitoringdevice that may be worn continuously and comfortably by a human oranimal subject for at least one week or more and more typically two tothree weeks or more. In one embodiment, the device is specificallydesigned to sense and record cardiac rhythm (i.e., electrocardiogram,ECG) data, although in various alternative embodiments one or moreadditional physiological parameters may be sensed and recorded. Thephysiological monitoring device includes a number of features tofacilitate and/or enhance the patient experience, to make diagnosis ofcardiac arrhythmias more accurate, and to make manufacture of the devicemore simple and cost effective.

In some embodiments, an electronic device for monitoring physiologicalsignals in a mammal comprises:

-   -   at least two flexible wings extending laterally from a rigid        housing, wherein the flexible wings comprise a first set of        materials which enable the wings to conform to a surface of the        mammal and the rigid housing comprises a second set of        materials;    -   a printed circuit board assembly housed within the rigid        housing, wherein the rigid housing is configured to prevent        deformation of the printed circuit board in response to movement        of the mammal;    -   at least two electrodes embedded within the flexible wings, the        electrodes configured to provide conformal contact with the        surface of the mammal and to detect the physiological signals of        the mammal;    -   at least two electrode traces embedded within the wings and        mechanically decoupled from the rigid housing, the electrode        traces configured to provide conformal contact with the surface        of the mammal and transmit electrical signals from the        electrodes to the printed circuit board assembly; and,    -   at least one hinge portion connecting the wings to the rigid        housing, the hinge portions configured to flex freely at the        area where it is joined to the rigid housing.

In certain embodiments, each wing may comprise an adhesive. Inembodiments, the electrodes can be in the same plane as the adhesive. Incertain embodiments, each wing comprises at least one rim, wherein therim is thinner than an adjacent portion of each wing. The rigid housingmay further comprise dimples configured to allow for airflow between therigid housing and the surface of the mammal. In certain embodiments, therim is configured to prevent the release of a portion of the wing fromthe surface of the mammal. In some embodiments, an electronic device formonitoring physiological systems may comprise a measuring instrumentconfigured to detect motion signals in at least one axis. This measuringinstrument may be an accelerometer that can be configured to detectmotion signals in three axes.

In embodiments, the motion signals can be collected in time with thephysiological signals. In certain embodiments, a motion artifact isidentified when the physiological signals and the motion signals match.Further embodiments may call for an event trigger coupled to the printedcircuit board assembly. In some embodiments, the event trigger input issupported by the rigid housing so as to prevent mechanical stress on theprinted circuit board when the trigger is activated. The event triggermay be concave and larger than a human finger such that the eventtrigger is easily located. In certain embodiments, the electrode tracesare configured to minimize signal distortion during movement of themammal. In particular embodiments, gaskets may be used as a means forsealable attachment to the rigid housing.

In certain embodiments, a method for monitoring physiological signals ina mammal may comprise:

-   -   attaching an electronic device to the mammal, wherein the device        comprises:    -   at least two electrodes configured to detect physiological        signals from the mammal,    -   at least one measuring instrument configured to detect secondary        signals, and    -   at least two electrode traces connected to the electrodes and a        rigid housing; and,    -   comparing the physiological signals to the secondary signals to        identify an artifact.

In certain embodiments, identification of an artifact comprises acomparison between the frequency spectrum of the physiological signalsand the frequency spectrum of the secondary signals. In embodiments, thesecondary signals comprise motion signals that may be used to derive theactivity and position of the mammal. In certain embodiments, thesecondary signals are collected in three axes. In some embodiments, atertiary signal may also be collected. In certain embodiments, thesecondary signals comprise information about the connection between theelectronic device and the mammal. In some embodiments, the secondarysignals may be used to detect when the mammal is sleeping.

In some embodiments, a method of removing and replacing portions of amodular physiological monitoring device may comprise

-   -   applying the device of claim 1 to a mammal for a period of time        greater than 7 days and collecting physiological data;    -   using the device of claim 1 to detect a first set of        physiological signals;    -   removing the device of claim 1 from the surface of the mammal;    -   removing a first component from the device of claim 1; and,    -   incorporating the first component into a second physiological        monitoring device, the second physiological monitoring device        configured to detect a second set of physiological signals.

In some embodiments, the first component is electrically connected toother device components without the use of a permanent connection. Insome embodiments, the device may further comprise spring connections. Incertain embodiments, the first component may be preserved for a seconduse by a rigid housing to prevent damage. In particular embodiments, thefirst component is secured within a device by a mechanism that iscapable of re-securing a second component once the first component isremoved.

These and other aspects and embodiments of the invention are describedin greater detail below, with reference to the drawing figures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A and 1B are perspective and exploded views, respectively, of aphysiological monitoring device, according to one embodiment;

FIGS. 2A and 2B are top perspective and bottom perspective views,respectively, of a printed circuit board assembly of the physiologicalmonitoring device;

FIGS. 3A-E are perspective and exploded views of a flexible body andgasket of the physiological monitoring device;

FIG. 4 is an exploded view of a rigid housing of the physiologicalmonitoring device;

FIG. 5A-B is a perspective view of a battery holder of the physiologicalmonitoring device;

FIGS. 6A and 6B are cross sectional views of the physiologicalmonitoring device;

FIG. 7 is an exploded view of the physiological monitoring deviceincluding a number of optional items, according to one embodiment;

FIGS. 8A and 8B are perspective views of two people wearing thephysiological monitoring device, illustrating how the device bends toconform to body movement and position; and

FIGS. 9A-9F illustrate various steps for applying the physiologicalmonitor to a patient's body, according to one embodiment.

DETAILED DESCRIPTION

The following description is directed to a number of variousembodiments. The described embodiments, however, may be implementedand/or varied in many different ways without departing from the scope ofthe invention. For example, the described embodiments may be implementedin any suitable device, apparatus, or system to monitor any of a numberof physiological parameters. For example, the following discussionfocuses primarily on long-term, patch-based cardiac rhythm monitoringdevices. In one alternative embodiment, a physiological monitoringdevice may be used, for example, for pulse oximetry and diagnosis ofobstructive sleep apnea. In various alternative embodiments, one size ofphysiological monitor may be used for adult patients and another sizemay be used for pediatric patients. The method of using a physiologicalmonitoring device may also vary. In some cases, a device may be worn forone week or less, while in other cases, a device may be worn for atleast seven days and/or for more than seven days, for example betweenfourteen days and twenty-one days or even longer. Many other alternativeembodiments and applications of the described technology are possible.Thus, the following description is provided for exemplary purposes only.Throughout the specification, reference may be made to the term“conformal.” It will be understood by one of skill in the art that theterm “conformal” as used herein refers to a relationship betweensurfaces or structures where a first surface or structure fully adaptsto the contours of a second surface or structure.

Referring to FIGS. 1A and 1B, perspective and exploded views of oneembodiment of a physiological monitoring device 100 are provided. Asseen in FIG. 1A, physiological monitoring device 100 may include aflexible body 110 coupled with a watertight, rigid housing 115. Flexiblebody 110 (which may be referred to as “flexible substrate” or “flexibleconstruct”) typically includes two wings 130, 131, which extendlaterally from rigid housing 115, and two flexible electrode traces 311,312, each of which is embedded in one of wings 130, 131. Each electrodetrace 311, 312 is coupled, on the bottom surface of flexible body 110,with a flexible electrode (not visible in FIG. 1A). The electrodes areconfigured to sense heart rhythm signals from a patient to whichmonitoring device 100 is attached. Electrode traces 311, 312 thentransmit those signals to electronics (not visible in FIG. 1A) housed inrigid housing 115. Rigid housing 115 also typically contains a powersource, such as one or more batteries.

As will be explained in further detail below, the combination of ahighly flexible body 110, including flexible electrodes and electrodetraces 311, 312, with a very rigid housing 115 may provide a number ofadvantages. For example, flexible body 110 includes a configuration andvarious features that facilitate comfortable wearing of device 100 by apatient for fourteen (14) days or more without removal. Rigid housing115, which typically does not adhere to the patient in the embodimentsdescribed herein, includes features that lend to the comfort of device100. Rigid housing 115 also protects the electronics and power sourcecontained in housing 120, enhances the ability of a patient to providean input related to a perceived cardiac event, and allows for simplemanufacturing and reusability of at least some of the contents ofhousing 115. These and other features of physiological monitoring device100 are described in greater detail below.

Referring now to FIG. 1B, a partially exploded view of physiologicalmonitoring device 100 illustrates component parts that make up, and thatare contained within, rigid housing 115 in greater detail. In thisembodiment, rigid housing 115 includes an upper housing member 140,which detachably couples with a lower housing member 145. Sandwichedbetween upper housing member 140 and lower housing member 145 are anupper gasket 370, and a lower gasket 360 (not visible on FIG. 1B butjust below upper gasket 370). Gaskets 370, 360 help make rigid housingmember 115 watertight when assembled. A number of components ofmonitoring device 100 may be housed between upper housing member 140 andlower housing member 145. For example, in one embodiment, housing 115may contain a portion of flexible body 110, a printed circuit boardassembly (PCBA) 120, a battery holder 150, and two batteries 160.Printed circuit board assembly 120 is positioned within housing 115 tocontact electrode traces 311, 312 and batteries 160. In variousembodiments, one or more additional components may be contained withinor attached to rigid housing 115. Some of these optional components aredescribed further below, in reference to additional drawing figures.

Battery holder 150, according to various alternative embodiments, mayhold two batteries (as in the illustrated embodiment), one battery, ormore than two batteries. In other alternative embodiments, other powersources may be used. In the embodiment shown, battery holder 150includes multiple retain tabs 153 for holding batteries 160 in holder150. Additionally, battery holder 150 includes multiple feet 152 toestablish correct spacing of batteries 160 from the surface of PCBA 120and ensure proper contact with spring fingers 235 and 236. Springfingers 235 and 236 are used in this embodiment rather than solderingbatteries 160 to PCBA 120. Although soldering may be used in alternativeembodiments, one advantage of spring fingers 235 and 236 is that theyallow batteries 160 to be removed from PCBA 120 and holder 150 withoutdamaging either of those components, thus allowing for multiple reusesof both. Eliminating solder connections also simplifies and speeds upassembly and disassembly of monitoring device 100.

In some embodiments, upper housing member 140 may act as a patient eventtrigger. When a patient is wearing physiological monitoring device 100for cardiac rhythm monitoring, it is typically advantageous for thepatient to be able to register with device 100 (i.e., log into thedevice's memory) any cardiac events perceived by the patient. If thepatient feels what he/she believes to be an episode of heart arrhythmia,for example, the patient may somehow trigger device 100 and thus providea record of the perceived event. At some later time, the patient'srecorded perceived event could be compared with the patient's actualheart rhythm, recorded by device 100, and this may help determinewhether the patient's perceived events correlate with actual cardiacevents. One problem with patient event triggers in currently availablewearable cardiac rhythm monitoring devices, however, is that a smalltrigger may be hard to find and/or activate, especially since themonitoring device is typically worn under clothing. Additionally,pressing a trigger button may affect the electronics and/or theelectrodes on the device in such a way that the recorded heart rhythmsignal at that moment is altered simply by the motion caused to thedevice by the patient triggering. For example, pressing a trigger mayjar one or both of the electrodes in such a way that the recorded heartrhythm signal at that moment appears like an arrhythmia, even if noactual arrhythmia event occurred. Additionally, there is a chance thatthe trigger may be inadvertently activated, for instance while sleepingor laying on the monitoring device.

In the embodiment shown in FIGS. 1A and 1B, however, rigid housing 115is sufficiently rigid, and flexible body 110 is sufficiently flexible,that motion applied to housing 115 by a patient may rarely or ever causean aberrant signal to be sensed by the electrodes. In this embodiment,the central portion of upper housing member 140 is slightly concave and,when pressed by a patient who is wearing device 100, this centralportion depresses slightly to trigger a trigger input on PCBA 120.Because the entire upper surface of rigid housing 115 acts as thepatient event trigger, combined with the fact that it is slightlyconcave, it will generally be quite easy for a patient to find and pushdown the trigger, even under clothing. Additionally, the concave natureof the button allows it to be recessed which protects it frominadvertent activations. Thus, the present embodiment may alleviate someof the problems encountered with patient event triggers on currentlyavailable heart rhythm monitors. These and other aspects of the featuresshown in FIGS. 1A and 1B will be described in further detail below.

Referring now to FIGS. 2A and 2B, printed circuit board assembly 120 (or“PCBA”) may include a top surface 220, a bottom surface 230, a patienttrigger input 210 and spring contacts 235, 236, and 237. Printed circuitboard assembly 120 may be used to mechanically support and electricallyconnect electronic components using conductive pathways, tracks orelectrode traces 311, 312. Furthermore, because of the sensitive natureof PCBA 120 and the requirement to mechanically interface with rigidbody 115, it is beneficial to have PCBA 120 be substantially rigidenough to prevent unwanted deflections which may introduce noise orartifact into the ECG signal. This is especially possible during patienttrigger activations when a force is transmitted through rigid body 115and into PCBA 120. One way to ensure rigidity of the PCBA is to ensurethat the thickness of the PCBA is relatively above a certain value. Forexample, a thickness of at least about 0.08 cm is desirable and, morepreferably, a thickness of at least about 0.17 cm is desirable. In thisapplication, PCBA 120 may also be referred to as, or substituted with, aprinted circuit board (PCB), printed wiring board (PWB), etched wiringboard, or printed circuit assembly (PCA). In some embodiments, a wirewrap or point-to-point construction may be used in addition to, or inplace of, PCBA 120. PCBA 120 may include analog circuits and digitalcircuits.

Patient trigger input 210 may be configured to relay a signal from apatient trigger, such as upper housing member 140 described above, toPCBA 120. For example, patient trigger input 210 may be a PCB switch orbutton that is responsive to pressure from the patient trigger (i.e.,the upper surface of upper housing portion 140). In various embodiments,patient trigger input 210 may be a surface mounted switch, a tactileswitch, an LED illuminated tactile switch, or the like. In someembodiments, patient trigger input 210 may also activate an indicator,such as an LED.

One important challenge in collecting heart rhythm signals from a humanor animal subject with a small, two-electrode physiological monitoringdevice such as device 100 described herein, is that having only twoelectrodes can sometimes provide a limited perspective when trying todiscriminate between artifact and clinically significant signals. Forexample, when a left-handed patient brushes her teeth while wearing asmall, two-electrode physiological monitoring device on her left chest,the tooth brushing may often introduce motion artifact that causes arecorded signal to appear very similar to Ventricular Tachycardia, aserious heart arrhythmia. Adding additional leads (and, hence, vectors)is the traditional approach toward mitigating this concern, but this istypically done by adding extra wires adhered to the patient's chest invarious locations, such as with a Holter monitor. This approach is notconsistent with a small, wearable, long term monitor such asphysiological monitoring device 100.

An alternate approach to the problem described above is to provide oneor more additional data channels to aid signal discrimination. In someembodiments, for example, device 100 may include a data channel fordetecting patch motion. In certain embodiments, an accelerometer mayprovide patch motion by simply analyzing the change in magnitude of asingle axis measurement, or alternatively of the combination of allthree axes. The accelerometer may record device motion at a sufficientsampling rate to allow algorithmic comparison of its frequency spectrumwith that of the recorded ECG signal. If there is a match between themotion and recorded signal, it is clear that the device recording inthat time period is not from a clinical (e.g., cardiac) source, and thusthat portion of the signal can be confidently marked as artifact. Thistechnique may be particularly useful in the tooth brushing motionexample aforementioned, where the rapid frequency of motion as well asthe high amplitude artifact is similar to the heart rate and morphology,respectively, of a potentially life-threatening arrhythmia likeVentricular Tachycardia.

In some embodiments, using the magnitude of all three axes for such ananalysis would smooth out any sudden changes in values due to a shift inposition rather than a change in activity. In other embodiments, theremay be some advantage in using a specific axis of measurement such asalong the longitudinal axis of the body to focus on a specific type ofartifact introduced by upward and downward movements associated withwalking or running. In a similar vein, the use of a gyroscope inconjunction with the accelerometer may provide further resolution as tothe nature of the motion experienced. While whole body movements may besufficiently analyzed with an accelerometer on its own, specific motionof interest such as rotational motion due to arm movement issufficiently complex that an accelerometer alone might not be able todistinguish.

In addition to detecting motion artifact, an accelerometer tuned to thedynamic range of human physical activities may provide activity levelsof the patient during the recording, which can also enhance accuracy ofalgorithmic true arrhythmia detection. Given the single-lead limitationof device 100, arrhythmias that require observation of less prominentwaves (e.g. P-wave) in addition to rate changes such as SupraventricularTachycardia pose challenges to both computerized algorithms as well asthe trained human eye. This particular arrhythmia is also characterizedby the sudden nature of its onset, which may be more confidentlydiscriminated from a non-pathological Sinus Tachycardia if a suddensurge in the patient's activity level is detected at the same time asthe increase in heart rate. Broadly speaking, the provision of activityinformation to clinical professionals may help them discriminate betweenexercise-induced arrhythmia versus not. As with motion artifactdetection, a single-axis accelerometer measurement optimized to aparticular orientation may aid in more specifically determining theactivity type such as walking or running. This additional informationmay help explain symptoms more specifically and thereby affect thesubsequent course of therapeutic action.

In certain embodiments, an accelerometer with 3 axes may conferadvantages beyond what magnitude of motions can provide. When thesubject is not rapidly moving, 3-dimensional accelerometer readings mayapproximate the tilt of PCBA 120, and therefore body orientationrelative to its original orientation. The original body orientation canbe assumed to be in either an upright or supine position which isrequired for appropriate positioning and application of the device tothe body. This information may aid in ruling out certain cardiacconditions that manifest as beat-to-beat morphology changes, such ascardiac alternans where periodic amplitude changes are observed, oftenin heart failure cases. Similar beat-to-beat morphology changes areobservable in healthy subjects upon shift in body position due to theshift in heart position relative to the electrode vector, for examplefrom an upright to a slouching position. By design, the single-channeldevice 100 does not have an alternate ECG channel to easily rule outpotential pathological shifts in morphology, however, correlation withshifts in body orientation will help explain these normal changes andavoid unnecessary treatment due to false diagnosis.

In other embodiments, the accelerometer may also be used as a sleepindicator, based on body orientation and movement. When presentingclinical events (e.g., pauses), it is diagnostically helpful to be ableto present information in a manner that clearly separates events thatoccurred during sleep from those during waking hours. In fact, certainalgorithms such as for ECG-derived respiratory rate only make sense torun when the patient is in a relatively motionless state and thereforesubtle signal modulation introduced by chest movement due to breathingis observable. Respiratory rate information is useful as one channel ofinformation necessary to detect sleep apnea in certain patientpopulations.

In certain embodiments, the accelerometer may also be used to detectfree-falls, such as fainting. With an accelerometer, device 100 may beable to mark fainting (syncope) and other free-fall events withoutrelying on patient trigger. In order to allow timely detection of suchcritical events, yet considering the battery and memory limitations of asmall, wearable device such as device 100, acquisition of accelerometerreadings may be done in bursts, where only interesting information suchas a potential free fall is written to memory at a high sampling rate.An expansion of this event-trigger concept is to use specific tappingmotions on device 100 as a patient trigger instead of or in conjunctionwith the button previously described. The use and detection of multipletypes of tapping sequences may provide better resolution and accuracyinto what exactly the patient was feeling, instead of relying on thepatient to manually record their symptom and duration in a trigger logafter the fact. An example of such added resolution is to indicate theseverity of the symptom by the number of sequential taps.

Alternatively, in other embodiments, an optical sensors may be used todistinguish between device motion and patient body motion. Further, inadditional embodiments, the device may not require a button or trigger.

Another optional data channel that may be added to physiologicalmonitoring device 100 is a channel for detecting flex and/or bend ofdevice 100. In various embodiments, for example, device 100 may includea strain gauge, piezoelectric sensor or optical sensor to detect motionartifact in device 100 itself and thus help to distinguish betweenmotion artifact and cardiac rhythm data. Yet another optional datachannel for device 100 may be a channel for detecting heart rate. Forexample, a pulse oximeter, microphone or stethoscope may provide heartrate information. Redundant heart rate data may facilitatediscrimination of ECG signals from artifact. This is particularly usefulin cases where arrhythmia such as Supraventricular Tachycardia isinterrupted by artifact, and decisions must be made whether the episodewas actually multiple shorter episodes or one sustained episode. Anotherdata channel may be included for detecting ambient electrical noise. Forexample, device 100 may include an antenna for picking upelectromagnetic interference. Detection of electromagnetic interferencemay facilitate discrimination of electrical noise from real ECG signals.Any of the above-described data channels may be stored to support futurenoise discrimination or applied for immediate determination of clinicalvalidity in real-time.

With reference now to FIGS. 3A and 3B, flexible body 110 is shown ingreater detail. As illustrated in FIG. 3A, flexible body 110 may includewings 130, 131, a thin border 133 (or “rim” or “edge”) around at leastpart of each wing 130, 131, electrode traces 311, 312, and a hingeportion 132 (or “shoulder”) at or near a junction of each wing 130, 131with rigid housing 115. Also shown in FIG. 3A is upper gasket 370, whichis not considered part of flexible body 110 for this description, butwhich facilitates attachment of flexible body 110 to rigid housing 115.

Hinge portions 132 are relatively thin, even more flexible portions offlexible body 110. They allow flexible body 110 to flex freely at thearea where it is joined to rigid housing 115. This enhances comfort,since when the patient moves, housing 115 can freely lift off of thepatient's skin. Electrode traces 311, 312 are also very thin andflexible, to allow for patient movement without signal distortion.Borders 133 are portions of flexible body 110 that is thinner thanimmediately adjacent portions and that provide for a smooth transitionfrom flexible body 110 to a patient's skin, thus preventing edge-liftand penetration of dirt or debris below flexible body 110.

As shown in greater detail in FIG. 3B, flexible body 110 may includemultiple layers. As mentioned previously, upper gasket 370 and lowergasket 360 are not considered part of flexible body 110 for the purposesof this description but are shown for completeness of description. Thisdistinction is for ease of description only, however, and should not beinterpreted to limit the scope of the claimed invention. Flexible body110 may include a top substrate layer 300, a bottom substrate layer 330,an adhesive layer 340, and flexible electrodes 350. Top and bottomsubstrate layers 300, 330 may be made of any suitable, flexiblematerial, such as one or more flexible polymers. Suitable flexiblepolymers can include, but are not limited to, polyurethane,polyethylene, polyester, polypropylene, nylon, teflon and carbonimpregnated vinyl. The material of substrate layers 300, 330 may beselected based on desired characteristics. For example, the material ofsubstrate layers 300, 330 may be selected for flexibility, resilience,durability, breathability, moisture transpiration, adhesion and/or thelike. In one embodiment, for example, top substrate layer 300 may bemade of polyurethane, and bottom substrate layer 330 may be made ofpolyethylene or alternatively polyester. In other embodiments, substratelayers 300, 330 may be made of the same material. In yet anotherembodiment, substrate layer 330 may contain a plurality of perforationsin the area over adhesive layer 340 to provide for even morebreathability and moisture transpiration. In various embodiments,physiological monitoring device 100 may be worn continuously by apatient for as many as 14-21 days or more, without removal during thetime of wear and with device 100 being worn during showering, exercisingand the like. Thus, the material(s) used and the thickness andconfiguration of substrate layers 300, 330 may be essential to thefunction of physiological monitoring device 100. In some embodiments,the material of substrate layers 300, 330 acts as an electric staticdischarge (ESD) barrier to prevent arcing.

Typically, top and bottom substrate layers 300, 330 are attached to oneanother via adhesive placed on one or both layers 300, 330. For example,the adhesive or bonding substance between substrate layers 300, 330 maybe an acrylic-based, rubber-based, or silicone-based adhesive. In otheralternative embodiments, flexible body 110 may include more than twolayers of flexible material.

In addition to the choice of material(s), the dimensions—thickness,length and width—of substrate layers 300, 330 may be selected based ondesired characteristics of flexible body 110. For example, in variousembodiments, the thickness of substrate layers 300, 330 may be selectedto give flexible body 110 an overall thickness of between about 0.1 mmto about 1.0 mm. According to various embodiments, flexible body 110 mayalso have a length of between about 7 cm and 15 cm and a width of about3 cm and about 6 cm. Generally, flexible body 110 will have a lengthsufficient to provide a necessary amount of separation betweenelectrodes 350. For example, a distance from the center of one electrode350 to the center of the other electrode 350 should be at least about6.0 cm and more preferably at least about 8.5 cm. This separationdistance may vary, depending on the application. In some embodiments,substrate layers 300, 330 may all have the same thickness.Alternatively, the two substrate layers 300, 330 may have differentthicknesses.

As mentioned above, hinge portions 132 allow the rigid body 115 to liftaway from the patient while flexible body 110 remains adhered to theskin. The functionality of hinge portions 132 is critical in allowingthe device to remain adhered to the patient throughout variousactivities that may stretch and compress the skin. Furthermore, hingeportions 132 allow for significantly improved comfort while wearing thedevice. Generally, hinge portions 132 will be sufficiently wide enoughto provide adequate lift of rigid body 115 without creating too large ofa peel force on flexible body 110. For example, in various embodiments,the width of hinge portion 132 should be at least about 0.25 cm and morepreferably at least about 0.75 cm.

Additionally, the shape or footprint of flexible body 110 may beselected based on desired characteristics. As seen in FIG. 3A, wings130, 131 and borders 133 may have rounded edges that give flexible body110 an overall “peanut” shape. However, wings 130, 131 can be formed inany number of different shapes such as rectangles, ovals, loops, orstrips. In the embodiment shown in FIGS. 3A and 3B, the footprint topsubstrate layer 300 is larger than the footprint of bottom substratelayer 330, with the extension of top substrate layer 300 forming borders133. Thus, borders 133 are made of the same polyurethane material thattop layer 300 is made of. Borders 133 are thinner than an adjacentportion of each wing 130, 131, since they includes only top layer 300.The thinner, highly compliant rim 133 will likely enhance adherence ofphysiologic monitoring device 100 to a patient, as it provides atransition from an adjacent, slightly thicker portion of wings 130, 131to the patient's skin and thus helps prevent the edge of device 110 frompeeling up off the skin. Border 133 may also help prevent the collectionof dirt and other debris under flexible body 110, which may help promoteadherence to the skin and also enhance the aesthetics of device 110. Inalternative embodiments, the footprint of substrate layers 300, 330 maybe the same, thus eliminating borders 133.

While the illustrated embodiments of FIGS. 1A-3B include only two wings130, 131, which extend from rigid housing 115 in approximately oppositedirections (i.e., at a 180-degree angle relative to each other), otherconfigurations are possible in alternative embodiments. For example, insome embodiments, wings 130, 131 may be arranged in an asymmetricalorientation relative to one another and/or one or more additional wingsmay be included. As long as sufficient electrode spacing is provided topermit physiological signal monitoring, and as long as wings 130, 131are configured to provide extended attachment to the skin, any suitableconfiguration and number of wings 130, 131 and electrode traces 311, 312may be used. The embodiments described above have proven to beadvantageous for adherence, patient comfort and accuracy of collectedheart rhythm data, but in alternative embodiments it may be possible toimplement alternative configurations.

Adhesive layer 340 is an adhesive that is applied to two portions of thebottom surface of bottom substrate layer 330, each portion correspondingto one of wings 130, 131. Adhesive layer 340 thus does not extend alongthe portion of bottom substrate layer 330 upon which rigid housing 115is mounted. Adhesive layer 340 may be made of any suitable adhesive,although certain adhesives have been found to be advantageous forproviding long term adhesion to patient skin with relative comfort andlack of skin irritation. For example, in one embodiment, adhesive layer340 is a hydrocolloid adhesive. In another embodiment, the adhesivelayer 340 is comprised of a hydrocolloid adhesive that containsnaturally-derived or synthetic absorbent materials which take upmoisture from the skin during perspiration.

Each of the two portions of adhesive layer 340 includes a hole, intowhich one of electrodes 350 fits. Electrodes 350 made of flexiblematerial to further provide for overall conformability of flexible body110. In one embodiment, for example, flexible electrodes 350 may be madeof a hydrogel 350. Electrodes 350 generally provide conformal,non-irritating contact with the skin to provide enhanced electricalconnection with the skin and reduce motion artifact. In someembodiments, hydrogel electrodes 350 may be punched into adhesive layer340, thus forming the holes and filling them with hydrogel electrodes350. In one alternative embodiment, electrodes 350 and adhesive 340 maybe replaced with an adhesive layer made of a conductive material, suchthat the entire adhesive layer on the underside of each wing 130, 131acts as an electrode. Such an adhesive layer may include a hybridadhesive/conductive substance or adhesive substance mixed withconductive elements or particles. For example, in one embodiment, suchan adhesive layer may be a hybrid of a hydrogel and a hydrocolloidadhesive.

As discussed above, in some embodiments, adhesive layer 340 may cover aportion of the underside of lower substrate layer 330, such that atleast a portion of the bottom side of flexible body 110 does not includeadhesive layer 340. As seen in FIG. 3A, hinges 132 may be formed in theflexible body 110 as portions of each wing 130, 131 on which adhesivelayer 340 is not applied. Hinge portions 132 are generally located at ornear the junction of flexible body 110 with rigid housing 115, and thusprovide for flexing of device 100 to accommodate patient movement. Insome embodiments, hinge portions 132 may have a width that is less thanthat of adjacent portions of wings 130, 131, thus giving device 100 its“peanut” shape mentioned above. As shown in FIG. 8, as a subject moves,device 100 flexes along with patient movement. Device flexion may besevere and is likely to occur many times during long term monitoring.Hinge portions 132 may allow for dynamic conformability to the subject,while the rigidity of rigid housing 115 may allow housing 115 to pop upoff the patient's skin during device flexion, thus preventing peeling ofthe device 100 off of the skin at its edge.

Flexible body 110 further includes two electrode traces 311, 312sandwiched between upper substrate layer 300 and lower substrate layer330. Each electrode trace 311, 312 may include an electrode interfaceportion 310 and an electrocardiogram circuit interface portion 313. Asillustrated in FIGS. 3C and 3D, ECG circuit interface portions 313 arein physical contact with spring fingers 237 and provide electricalcommunication with PCBA 120 when device 100 or zoomed-in device portion101 is assembled. Electrode interface portions 310 contact hydrogelelectrodes 350. Thus, electrode traces 311, 312 transmit cardiac rhythmsignals (and/or other physiological data in various embodiments) fromelectrodes 350 to PCBA 120.

The material and thickness of electrode traces 311, 312 are importantfor providing a desired combination of flexibility, durability andsignal transmission. For example, in one embodiment, electrode traces311, 312 may include a combination of silver (Ag) and silver chloride(AgCl). The silver and silver chloride may be disposed in layers. Forexample, one embodiment of electrode traces 311, 312 may include a toplayer of silver, a middle layer of carbon impregnated vinyl, and abottom (patient-facing) layer of silver chloride. In another embodiment,both top and bottom layers of electrode traces 311, 312 may be made ofsilver chloride. In one embodiment, the top and bottom layers may beapplied to the middle layer in the form of silver ink and silverchloride ink, respectively. In an alternative embodiment, each electrodetrace may include only two layers, such as a top layer of silver and abottom layer of silver chloride. In various embodiments, the material ofa bottom layer of each electrode trace 311, 312, such as AgCl, may beselected to match the chemistry of the hydrogel electrodes 350 andcreate a half-cell with the body of the subject.

The thickness of the electrode traces 311, 312 may be selected tooptimize any of a number of desirable properties. For example, in someembodiments, at least one of the layers of electrode traces 311, 312 canbe of a sufficient thickness to minimize or slow depletion of thematerial from an anode/cathode effect over time. Additionally, thethickness may be selected for a desired flexibility, durability and/orsignal transmission quality. Flexible electrode traces 311, 312generally may help provide conformal contact with the subject's skin andmay help prevent electrodes 350 from peeling or lifting off of the skin,thereby providing strong motion artifact rejection and better signalquality by minimizing transfer of stress to electrodes 350.

As mentioned above, in some embodiments, top gasket 370 and bottomgasket 360 may be attached upper substrate 300 and lower substrate 330of flexible body 110. Gaskets 360, 370 may be made of any suitablematerial, such as urethane, which provides a water tight seal betweenthe upper housing member 140 and lower housing member 145 of rigidhousing 115. In one embodiment, top gasket 370 and/or bottom gasket 360may include an adhesive surface. FIG. 3E depicts yet another embodimentwhere top gasket 370 includes tabs 371 that protrude away from theprofile of top housing 140 while still being adhered to upper substrate300. The tabs 371 cover a portion of electrode traces 311, 312 andprovide a strain relief for the traces at the point of highest stresswhere the flexible body meets the rigid housing.

With reference now to FIG. 4, upper housing member 140 and lower housingmember 145 of rigid housing 115 are shown in greater detail. Upper andlower housing members 140, 145 may be configured, when coupled togetherwith gaskets 360, 370 in between, to form a watertight enclosure forcontaining PCBA 120, battery holder 150, batteries 160 and any othercomponents contained within rigid housing 115. Housing members 140, 145may be made of any suitable material to protect internal components,such as water resistant plastic. In one embodiment, upper housing member140 may include a rigid sidewall 440, a light pipe 410 to transmitvisual information from the LEDs on the PCBA through the housing member,a slightly flexible top surface 420, and an inner trigger member 430extending inward from top surface 420. Top surface 420 is configured tobe depressed by a patient when the patient perceives what he or shebelieves to be an arrhythmia or other cardiac event. When depressed, topsurface 420 depresses inner trigger member 430, which contacts andactivates trigger input 210 of PCBA 120. Additionally, as discussedpreviously, top surface 420 may have a concave shape (concavity facingthe inside of housing 115) to accommodate the shape of a finger. It isbelieved that the design of upper housing member 140 isolates activationof the trigger input 210 from electrodes 350, thereby minimizingartifact in the data recording.

With continued reference to FIG. 4, lower housing member 145 may beconfigured to detachably connect with upper housing member 140 in such away that housing members 140, 145 may be easily attached and detachedfor reusability of at least some of the component parts of monitoringdevice 100. In some embodiments, a bottom surface 445 (patient facingsurface) of lower housing member 145 may include multiple dimples 450(or “bumps,” “protrusions” or the like), which will contact thepatient's skin during use. Dimples 450 may allow for air flow betweenbottom surface 445 and the patient's skin, thus preventing a seal fromforming between bottom surface 445 and the skin. It is believed thatdimples 450 improve comfort and help prevent a perception in currentlyavailable devices in which the patient feels as if monitoring device 100is falling off when it housing 115 lifts off the skin and breaks a sealwith the skin. In yet another embodiment the bottom surface 445 of lowerhousing member 450 may include multiple divots (recesses instead ofprotrusions) to prevent a seal from forming.

Referring now to FIG. 5A, battery holder 150 is shown in greater detail.Battery holder 150 may be made of plastic or other suitable material, isconfigured to be mounted to PCBA 120 and subsequently attached to rigidhousing 115, and is capable of holding two batteries 160 (FIG. 1B). Inalternative embodiments, battery holder 150 may be configured to holdone battery or more than two batteries. A plurality of protrusions 152provide a stable platform for batteries 160 to be positioned a fixeddistance above the surface of PCBA 120, avoiding unwanted contact withsensitive electronic components yet providing for adequate compressionof spring contacts 235 (FIG. 5B). Protrusions 153 lock batteries 160into position and resist the upward force on the batteries from springcontacts 235. Battery holder 150 also positions batteries appropriately160 to provide for adequate compression of spring contacts 236. Use ofbattery holder 150 in conjunction with spring contacts 235 and 236allows for batteries 160 to be electrically connected to PCBA 120 whilestill having additional electronic components between batteries 160 andPCBA 120 and maintain a very compact assembly. Battery holder 150 mayinclude a flexible hook 510 which engages a corresponding rigid hook 440of upper housing member 140. Under normal assembly conditions theflexible hook 510 remains securely mated with rigid hook 440. Fordisassembly, flexible hook 510 can be pushed and bent using anappropriate tool passed through top housing 140 causing it to disengagefrom rigid hook 440 and subsequently allow top housing 140 to beremoved.

With reference now to FIGS. 6A and 6B, physiological monitoring device100 is shown in side view cross-section. As shown in 6A, physiologicalmonitoring device 100 may include flexible body 110 coupled with rigidhousing 115. Flexible body 110 may include top substrate layer 300,bottom substrate layer 330, adhesive layer 340 and electrodes 350.Electrode traces 311, 312 are also typically part of flexible body 110and are embedded between top substrate layer 300 and bottom substratelayer 330, but they are not shown in FIG. 6. Flexible body 110 forms twowings 130, 131, extending to either side of housing 115, and a border133 surrounding at least part of each wing 130, 131. Rigid housing 115may include an upper housing member 140 coupled with a lower housingmember 145 such that it sandwiches a portion of flexible body 110 inbetween and provides a watertight, sealed compartment for PCBA 120.Upper housing member 140 may include inner trigger member 430, and PCBAmay include patient trigger member 210. As discussed previously, lowerhousing member 145 may include multiple dimples 450 or divots to enhancethe comfort of the monitoring device 100.

It is desirable that PCBA 120 is sufficiently rigid to prevent bendingand introducing unwanted artifact into the signal. In certainembodiments, an additional mechanism to reduce and prevent unwantedbending of PCBA 120 may be used. This mechanism is shown in FIG. 6B.Support post 460 is integral to lower housing 145 and is positioneddirectly under patient trigger input 210. During patient symptomtriggering, upper housing member 140 is depressed, engaging innertrigger mechanism 430 and transmitting a force through patient triggerinput 210 into PCBA 120. The force is further transmitted through PCBA120 and into support post 460 without creating a bending moment, thusavoiding unwanted artifact.

Referring to FIG. 7, in some embodiments, physiological monitoringdevice 100 may include one or more additional, optional features. Forexample, in one embodiment, monitoring device 100 may include aremovable liner 810, a top label 820, a device identifier 830 and abottom label 840. Liner 810 may be applied over a top surface offlexible member 110 to aid in the application of device 100 to thesubject. As is described in further detail below, liner 810 may helpsupport borders 133 of flexible body 110, as well as wings 130, 131,during removal of one or more adhesive covers (not shown) that coveradhesive surface 340 before use. Liner 810 may be relative rigid and/orfirm, to help support flexible body 110 during removal of adhesivecovers. In various embodiments, for example, liner 810 may be made ofcardboard, thick paper, plastic or the like. Liner 810 typicallyincludes an adhesive on one side for adhering to the top surface ofwings 130, 131 of flexible body 110.

Labels 820, 840 may be any suitable labels and may include producename(s), manufacturer name(s), logo(s), design(s) and/or the like. Theymay be removable or permanently attached upper housing member 140 and/orlower housing member 145, although typically they will be permanentlyattached, to avoid unregulated reuse and/or resale of the device by anunregistered user. Device identifier 830 may be a barcode sticker,computer readable chip, RFID, or the like. Device identifier 830 may bepermanently or removably attached to PCBA 120, flexible body 110 or thelike. In some embodiments, it may be beneficial to have deviceidentifier 830 stay with PCBA 120.

Referring now to FIGS. 8A and 8B, physiological monitoring device 100generally includes hinge portions 132 at or near the juncture of eachwing 130, 131 with rigid housing 115. Additionally, each wing 130, 131is typically adhered to the patient via adhesive layers 340, while rigidbody 115 is not adhered to the patient and is thus free to “float”(i.e., move up and down) over the patient's skin during movement andchange of patient position. In other words, when the patient's chestcontracts, rigid housing pops up or floats over the skin, thusminimizing stress on device 100, enhancing comfort, and reducing thetendency of wings 130, 131 to peel off of the skin. The advantageprovided by the combination of the floating rigid body 115 and theadhered wings 130, 131 is illustrated in FIGS. 8A and 8B. In FIG. 8A, apatient is sleeping, and in FIG. 8B, a patient is playing golf. In bothexamples, monitoring device 100 is squeezed together by the patient'sbody, causing rigid housing 115 to float above the skin as wings 130,131 move closer together. This advantage of a floating, non-attachedportion of a physiological monitoring device is described in furtherdetail in U.S. Pat. No. 8,560,046, which was previously incorporated byreference.

Referring now to FIGS. 9A-9F, one embodiment of a method for applyingphysiological monitoring device 100 to the skin of a human subject isdescribed. In this embodiment, before the first step shown in FIG. 9A,the patient's skin may be prepared, typically by shaving a small portionof the skin on the left chest where device 100 will be placed and thenabrading and/or cleaning the shaved portion. As shown in FIG. 9A, oncethe patient's skin is prepared, a first step of applying device 100 mayinclude removing one or both of two adhesive covers 600 from adhesivelayers 340 on the bottom surface of device 100, thus exposing adhesivelayers 340. As illustrated in FIG. 9B, the next step may be to applydevice 100 to the skin, such that adhesive layer 340 adheres to the skinin a desired location. In some embodiments, one adhesive cover 600 maybe removed, the uncovered adhesive layer 340 may be applied to the skin,and then the second adhesive cover 600 may be removed, and the secondadhesive layer 340 may be applied to the skin. Alternatively, bothadhesive covers 600 may be removed before applying device 100 to theskin. While adhesive covers 600 are being removed, liner 810 acts as asupport for flexible body 110, provides the physician or other user withsomething to hold onto, and prevents flexible body 110 and borders 133of flexible body 110 from folding in on themselves, forming wrinkles,etc. As described above, liner 810 may be made of a relatively stiff,firm material to provide support for flexible body 110 duringapplication of device 100 to the skin. Referring to FIG. 9C, afterdevice 100 has been applied to the skin, pressure may be applied toflexible body 110 to press it down onto the chest to help ensureadherence of device 100 to the skin.

In a next step, referring to FIG. 9D, liner 810 is removed from (peeledoff of) the top surface of flexible body 110. As shown in FIG. 9E, onceliner 810 is removed, pressure may again be applied to flexible body 110to help ensure it is adhered to the skin. Finally, as shown in FIG. 9F,upper housing member 140 may be pressed to turn on physiologicalmonitoring device 140. This described method is only one embodiment. Inalternative embodiments, one or more steps may be skipped and/or one ormore additional steps may be added.

When a desired monitoring period has ended, such as about 14-21 days insome cases, a patient (or physician, nurse or the like) may removephysiological monitoring device 100 from the patient's skin, placedevice 100 in a prepaid mailing pouch, and mail device 100 to a dataprocessing facility. At this facility, device 100 may be partially orcompletely disassembled, PCBA 120 may be removed, and storedphysiological data, such as continuous heart rhythm information, may bedownloaded from PCBA 120. The data may then be analyzed by any suitablemethod and then provided to a physician in the form of a report. Thephysician may then discuss the report with the patient. PCBA 120 and/orother portions of device 100, such as rigid housing 115, may be reusedin the manufacture of subsequent devices for the same or other patients.Because device 100 is built up as a combination of several removablycoupled parts, various parts may be reused for the same embodiment ordifferent embodiments of device 100. For example, PCBA 120 may be usedfirst in an adult cardiac rhythm monitor and then may be used a secondtime to construct a monitor for sleep apnea. The same PCBA 120 mayadditionally or alternatively be used with a differently sized flexiblebody 110 to construct a pediatric cardiac monitor. Thus, at least someof the component parts of device 100 may be interchangeable andreusable.

Advantageously, physiological monitoring device 100 may provide longterm adhesion to the skin. The combination of the configuration offlexible and conformal body 110, the watertight, low profileconfiguration of rigid housing 115, and the interface between the twoallows device 100 to compensate for stress caused as the skin of thesubject stretches and bends. As a result, device 100 may be worncontinuously, without removal, on a patient for as many as 14-21 days ormore. In some cases, device 100 may be worn for greater or less time,but 14-21 days may often be a desirable amount of time for collectingheart rhythm data and/or other physiological signal data from a patient.

In various alternative embodiments, the shape of a particularphysiological monitoring device may vary. The shape, footprint,perimeter or boundary of the device may be circular, an oval,triangular, a compound curve or the like, for example. In someembodiments, the compound curve may include one or more concave curvesand one or more convex curves. The convex shapes may be separated by aconcave portion. The concave portion may be between the convex portionon the rigid housing and the convex portion on the electrodes. In someembodiments, the concave portion may correspond at least partially witha hinge, hinge region or area of reduced thickness between the body anda wing.

While described in the context of a heart monitor, the deviceimprovements described herein are not so limited. The improvementsdescribed in this application may be applied to any of a wide variety ofphysiological data monitoring, recording and/or transmitting devices.The improved adhesion design features may also be applied to devicesuseful in the electronically controlled and/or time released delivery ofpharmacological agents or blood testing, such as glucose monitors orother blood testing devices. As such, the description, characteristicsand functionality of the components described herein may be modified asneeded to include the specific components of a particular applicationsuch as electronics, antenna, power supplies or charging connections,data ports or connections for down loading or off loading informationfrom the device, adding or offloading fluids from the device, monitoringor sensing elements such as electrodes, probes or sensors or any othercomponent or components needed in the device specific function. Inaddition or alternatively, devices described herein may be used todetect, record, or transmit signals or information related to signalsgenerated by a body including but not limited to one or more of ECG, EEGand/or EMG.

While the above embodiments disclose the invention with respect to adata channel for collecting a single physiological signal, it iscontemplated that additional data channels can be include to collectadditional data, for example, device motion, device flex or bed, heartrate and/or ambient electrical noise.

Various embodiments of a physiological monitoring device and methods forusing it have been disclosed above. These various embodiments may beused alone or in combination, and various changes to individual featuresof the embodiments may be altered, without departing from the scope ofthe invention. For example, the order of various method steps may insome instances be changed, and/or one or more optional features may beadded to or eliminated from a described device. Therefore, thedescription of the embodiments provided above should not be interpretedas unduly limiting the scope of the invention as it is set forth in theclaims.

Various modifications to the implementations described in thisdisclosure may be made, and the generic principles defined herein may beapplied to other implementations without departing from the spirit orscope of this disclosure. Thus, the claims are not intended to belimited to the implementations shown herein, but are to be accorded thewidest scope consistent with this disclosure, the principles and thenovel features disclosed herein.

Certain features that are described in this specification in the contextof separate embodiments also can be implemented in combination in asingle embodiment. Conversely, various features that are described inthe context of a single embodiment also can be implemented in multipleembodiments separately or in any suitable subcombination. Moreover,although features may be described above as acting in certaincombinations and even initially claimed as such, one or more featuresfrom a claimed combination can in some cases be excised from thecombination, and the claimed combination may be directed to asubcombination or variation of a subcombination.

Similarly, while operations are depicted in the drawings in a particularorder, such operations need not be performed in the particular ordershown or in sequential order, or that all illustrated operations beperformed, to achieve desirable results. Further, the drawings mayschematically depict one more example processes in the form of a flowdiagram. However, other operations that are not depicted can beincorporated in the example processes that are schematicallyillustrated. For example, one or more additional operations can beperformed before, after, simultaneously, or between any of theillustrated operations. Moreover, the separation of various systemcomponents in the embodiments described above should not be interpretedas requiring such separation in all embodiments. Additionally, otherembodiments are within the scope of the following claims. In some cases,the actions recited in the claims can be performed in a different orderand still achieve desirable results.

1-20. (canceled)
 21. An electronic device for monitoring physiologicalsignals in a mammal, the device comprising: a plurality of flexiblewings extending laterally from a housing, each flexible wing configuredto conform to a surface of the mammal and comprising a lower substratelayer, an upper substrate layer, and a bottom surface comprising along-term adhesive, the long-term adhesive configured to adhere to theskin of the mammal; a hardware processor housed within the housing; aflexible electrode positioned on each flexible wing, each flexibleelectrode configured to provide conformal contact with a non-planarsurface of the skin of the mammal during movement of the mammal; anelectrode trace positioned between each upper substrate layer and eachlower substrate layer, each upper substrate layer comprising a rimextending horizontally outward beyond the corresponding lower substratelayer; a tab extending from the housing and positioned over eachelectrode trace, each tab configured to provide strain relief to thecorresponding electrode trace; and wherein each electrode trace extendsoutward from the housing, each flexible electrode and at least a portionof each electrode trace configured to remain conformal with the skin ofthe mammal during bending of the skin.
 22. The electronic device ofclaim 21, wherein each tab extends partially along the length of eachcorresponding electrode trace.
 23. The electronic device of claim 21,wherein each electrode trace conforms to an entire upper surface of eachcorresponding flexible electrode.
 24. The electronic device of claim 21,wherein the electrode traces comprise a first material and the flexibleelectrodes comprise a second material, the first material different fromthe second material.
 25. The electronic device of claim 21, wherein theelectrode traces are not relied upon for mechanical support.
 26. Theelectronic device of claim 21, wherein the housing comprises a firsthook, the first hook configured to engage a second hook, the second hookattached to a battery holder, the first hook more rigid than the secondhook.
 27. The electronic device of claim 21, wherein the housingcomprises a patient trigger configured to depress and record an instancein time of a perceived cardiac event.
 28. The electronic device of claim27, wherein the patient trigger covers a majority of the top surface ofthe housing.
 29. The electronic device of claim 27, further comprising asupport post positioned beneath the patient trigger, the support postconfigured to remain rigid during depression of the patient trigger suchthat force from depression of the patient trigger is transmitted throughthe hardware processor into the support post without creating a bendingmoment.
 30. The electronic device of claim 21, wherein the long-termadhesive comprises a pressure-sensitive adhesive.
 31. The electronicdevice of claim 21, wherein the rim is thinner in a vertical plane thanan adjacent portion of the wing and configured to reduce edge-lift ofthe flexible wing from the skin of the mammal.
 32. An electronic devicefor monitoring physiological signals in a mammal, the device comprising:a plurality of wings extending laterally from a housing, each flexiblewing configured to conform to a surface of the mammal and comprising alower substrate layer, an upper substrate layer, and a bottom surfacecomprising a long-term adhesive, the long-term adhesive configured toadhere to the skin of the mammal; a hardware processor housed within thehousing; a flexible electrode positioned on each flexible wing, eachflexible electrode configured to provide conformal contact with anon-planar surface of the skin of the mammal during movement of themammal; an electrode trace positioned between each upper substrate layerand each lower substrate layer, each upper substrate layer comprising arim extending horizontally outward beyond the corresponding lowersubstrate layer, the rim being thinner in a vertical plane than anadjacent portion of the flexible wing and configured to reduce edge-liftof the flexible wing from the skin of the mammal; and wherein eachelectrode trace extends outward from the housing, each flexibleelectrode and at least a portion of each electrode trace configured toremain conformal with the skin of the mammal during bending of the skin.33. The electronic device of claim 32, wherein each electrode traceconforms to an entire upper surface of each corresponding flexibleelectrode.
 34. The electronic device of claim 32, wherein the electrodetraces comprise a first material and the flexible electrodes comprise asecond material, the first material different from the second material.35. The electronic device of claim 32, wherein the electrode traces arenot relied upon for mechanical support.
 36. The electronic device ofclaim 32, wherein the housing comprises a patient trigger configured todepress and record an instance in time of a perceived cardiac event. 37.The electronic device of claim 32, wherein the housing comprises anupper housing member and a lower housing member, the upper housingmember configured to detachably connect to the lower housing member. 38.The electronic device of claim 37, further comprising an upper gasketand a lower gasket positioned between the upper housing member and thelower housing member.
 39. The electronic device of claim 33, wherein thelong-term adhesive is a hydrocolloid.